There has been a growing interest in quantum bit (qubit) research over the last decades to realize quantum computation, which will allow faster computation of complex problems, effective simulation of quantum phenomena, and encrypted quantum communication. Spins of electrons and nuclei of point defects in solids, so-called solid-state spin qubits, have been considered as leading contenders, since quantum devices based on solids can be easily integrated into modern electronic devices. In order to realize efficient control and readout of long-lived qubits, hybrid quantum systems consisting of coupled electron and nuclear spins in diamond have been suggested. In these systems, the single nuclear spin is used as long-lived quantum memories thanks to its long coherence time, while the electron spin serves as a readout gate and an ancillary qubit for initializing the nuclear spin. In my presentation, I’ll introduce hybrid spin qubits based on isolated deep defects in wide bandgap semiconductors such as diamond and silicon carbide, and their applications for quantum information processing and quantum metrology.